Summation metering system



Sept. 6 1927. 7 1,641,762

B. W. JONES SUMMATICN METERING SYSTEM Filed Feb. 17, 1927 Fig. l

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Inventor":

Ben amin \A/. Jones,

Patent ed Sept. 16,1927.

UNITEB STATES I ,6 6 PATENT oFmcn- BENJAMIN W. JONES, OE SCHENEOTADY,NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEWYORK.

amnion mn'rname srs'rml.

Application filed February 17, 1987; Serial No. 169,051.

My invention relates to a system and apparatus for obtaining electricalmeasurements. The invention is applicable to a wide variety of usesbut'is particularly useful for I 5 obtaining a measurement pro ortionalto the sum of the power outputs o a plurality of electric power stations'on'feeders located at the same or diiferent points by means of simpleand inexpensive ap aratus. Incarrying my invention into e ect I employone or more electron discharge devices of the three-electrode type withcurrent measuring means in series therewith. To obtain a power summationmeasurement I prefer to bias the grid of the-electron discharge devicewith a summation voltage proportional to the sum of the current outputsof the several stations and impress a voltage proportional to thecircuit voltage at the stations between the filament and plate of thedevice. By proper calibration of the apparatus the plate current willthen be proportional to the sum of the power outputs. at the severalstations. This scheme has the distinguishing feature that it isunnecessary to transmit any measurement current or currents between theseveral. stations and the grid of the electron discharge-device at the ation meter, and as a consequence errors due to changes in lineresistance of the metering circuits between stations are largelyeliminated. I The features of my invention which are believed to benovel and patentable will be pointed out in the claims appended hereto.For a better understandin of the invention reference is made-in theollowingdescription. to thetaccompanying drawing in wh ch Fig. 1represents an embodiment of the in- 49 vention suitable balancedpolyphase power sy 11S, and

2 representsair embodiment suitable for use olyphase power systems.

with unbalanced 1g. 1, 10 represents a sta- Referring to tion at whichit is urement indicative of the sum of the power outputs of feederstations 11, i2 and 13. En

this simple embodiment the feeders at tions 11, 12 and 13 are allsupplied by or are 549 connected to a coon distribution system indicatedat 14 and thus the power is supplied at the same or approximatelyproportional voltages at each station.

Station 10 may he a load despatchers oce 5 located any distance 'Eromthe other static apedances 24,25 and 26, such that the voltfor use withsingle phase or desired to obtain a meas- It ishere assumed that thevoltage and cur-' rent of the three-phase alternating currentdistribution system representedwill be balanced such that the current inany one phase and the volta e across anyphase will be representative othe current. and voltage of all phases. At station 10 is an ordinarythreeelectrode electron discharge device 15 havmg a hot cathode 16, agr1d 17 and a plate 18. The filament and grid are connected across onephase of the system- 14 and a direct current instrument 19 is includedin the plate circuit. 20 indicates a battery for heating the filament.

-A t stations 11, 12 and 13, current transformers 21, 22 and 23 aremcluded in the same phase of the three poly hasefeeder circuits and thesecondaries of these tr=- 11 dormers are short circuited by suitableimages across the secondaries of the transformers will be equallyproportional to the rimary current taking into consideration fferencesin the transformer ratios, if any. The secondaries of the three currenttransformers are connected in series in the same direction m that thesecondary volta w be added and this series circuit is connected betweenthe filament and grid of the electron discharge device 15. As a resultthe grid volta will proportional to the sum of the inpase currents'inthe ower feeders at stations 11, 12 d 13. he current transformers are inthe same phase across which the voltage connection is made so that thevoltages imdluon the grid and late of the electron discarge device willin an: under unity power factor conditions of the circuit.

By proper adjustment of the electron discharge device the plate currentcan be made a pro oately proportional to insphase'components of the idbi voltage and the voltage between 'a'ment and grid, or prortional tothe s of the power of the stations ll, 12 and 13, over a considerablerange of grid bias voltage. The plate voltage will not vary teriallyexcept under very unusual conditions so, as is o, the line voltage ofdistribution systems re mains approximately constant. Some current mayow in e plate circuit with no voltage on the id hut with line voltaacross the tube. '5 indication of the meter l9 don t condition will bemarked zero. 3 a

direct current meter 19 fthe metering arrangement may be considered astwo systems sim1lar to that shown. in F igl 1, the correspondingadditional parts'being represented by similar reference charactersfollowed by the letter a.. The direct current meterfl9' has twoindependentcoils which act together in the same way as a single coil ofany usual type of direct current instrument to produce accumulativemeasuring effects. This instrument is calibrated to give the sum ofthe'power ou'tputs at the three stations 11,

12 and 13. It is evident that the duplicate parts of Fig. 2'might beassociated with entirely independent power systems to obtain a powersummation measurement. Similarly, we could provide'the remaining circuitof the three-phase system with similar summation equipment.

If for any reason it was desirable to obtain a reading at 19proportional to the sum of the power outputs of stations 11 and 86 12less that at station 13, it could be accomthose skilled in the art.

plished by. merely reversing the secondary connections to the currenttransformers at station 13. Likewise the invention may be used simply asa power telemetering system for a. single feeder. I n

It will be evident thatno current flows in the series summation circuitbetween stations but that'these connections merely serve to, add orsubtract the volta es across the short-circuited secondaries o thecurrent transformers. The length or resistance of this series circuit istherefore immaterial,

and changes in its res1stance, such as might be caused by temperaturechanges or the addition of other stations, will not affect the operationaccuracy of the'system."

' While I have represented an indicating instrument at 19 and 19" thiscould be replaced or supplemented with a relay, alarm, or any otherdevice 'commonly employed in connection with metering equipment. In highvoltage systems it may be desirable to insert a step-down transformerbetween the hi h tension line and the vacuum tube. 05181 ways ofproducing the measurement voltages at the power stations will occur toIn accordance with the provisions of the patent statutes, I havedescribed the principle of operation of my invention, together with theapparatus which I now consider to represent the best embodiment thereof,but I desire to have it understood that the apparatus shown anddescribed is only illustrative and that the invention may be carried outby other means.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. Apparatus for obtaining a current proportional to the power flowingin an electric circuit comprising an electron discharge device havingfilament, grid and plate electrodes, connections for impressing avoltage betweenthe filament and plate of said device which isproportional to the voltage of the circuit, and connections forproducing a voltage/between the filament and grid of saidvdevice whichis proportional to the cur- -*rent flowing in the circuit.

2. Apparatus for obtaining a measurement of the power flowing in anelectric circuit comprising an electron discharge device havingfilament, grid and plate electrodes, connections for impressing avoltage proportional to the circuit voltage between the filament andplate of said device, current measuring means connected n series withsaid electron discharge device, and connections for impressing a voltagebetween the filament and grid of said device proportional to the currentof the circuit.

3. Apparatus for obtaining a current proportional to the power flowingin an alternating current circuit comprising an electron dischargedevice having filament, grid and plate electrodes, connections forimpressing a voltage between the filament and plate of said device whichis proportional to the circuit voltage, means forproducing a voltageproportional to the current of the circuit, and connections forimpressing said last mentioned voltage between the filament and grid ofsaid device, the circuit connections being such that the voltagesimpressed upon the grid and plate of the electron discharge device arein phase when the power factor of the alternating current circuit isunity. V

dwApparatus for obtaining a current proportional to the power flowing inan alternating current circuit comprising an electron discharge devicehaving hlament, grid and plate electrodes, connections for impressing avoltage between the filament and plate of said device which isproportional to the circuit voltage, a current transformer connected inthe circuit, an impedance connected across the secondary of saidtransformer, and connections for impressing the voltage across thesecondary of said transformer between the filament and grid of saidelectron dischar e device.

5. ower measuring apparatus for alternating current circuits comprisinganf'electron discharge device having filament, grid and pisteelectrodes; connections for impressing a voltage between the 'filementand plate of said device which is proportional ingfilament, grid andplate e ectrodes, and

'means for impressing a voltage between the filament and grid of saiddevice which is proportional to the current in an alternating currentcircuit comprising a current transformer connected in said circuit, animpedance short circuiting the secondary terminals of said transformer,and connections be tween said terminals and the filament-and grid ofsaid device.

7. A power measuring system for alternating current circuits comprisingan elec tron discharge device having filament,

'd and plate electrodes, connections, includihg a current measuringinstrument, tor irn pressin a voltage proportional to the circuit vota'ge between the filament end plate of said device, a lurality ofcurrent transformers connectc in ditierent branches of the circuit,impedances connected ecrom the secondary terminals of said transformersand connections for connecting the secondary terminals of saidtransformers in series and impressing the resultant voltage across thefilament and grid of said device.

8. A power summationsyst'em for electric power-circuits comprising anelectron discharge device havin filament grid and plate electrodes,circuits or impressinga vo tage across the filament and plate of saiddevice which is proportional to the voltage of said i power circuitsmeans for producing voltages proportional to the currents flowing insaid power circuits connections for im ressing the sum of said voltagesacross the ament and grid of said device and current measuring means inthe plate circuit of said device calibrated with the'apparatus to give asummation power measurement.

9. Summation measuring apparatus comprising a plurality of electrondischarge do vice measuring systems, each such system producing anelectron discharge current pro- 'portional to the quantity measuredthereby,

current measurin means having at number oi windings eque 111 number :tothe meesur mg systems, suid windings being arranged to produceaccumulative measurin efiects, and.

circuit connections for conveyln the electron discharge currents of saisystems through said coils.

in witness whereof I have hereunto set my hand this 15th day ofFebruary, 1927.

BENJAMIN w; Jones.

